Container for washing of cellulose pulp



M y 1963 .1. er. c. RICHTER CONTAINER FOR WASHING OF CELLULOSE PULP 2 Sheets-Sheet 1 Filed March 24, 1961 e 5 mm n 3 M Wm m 7 fl M M m 8 2 Sheets-Sheet 2 May 7, 1963 J. c. F. c. RICHTER CONTAINER FOR WASHING OF CELLULOSE PULP Filed March 24, 1961 NTOR.

CGNTAKNER FOR WASHING OF CELLULOSE FULP Johan 6. F. C. Richter, St. Jean Cap Fer-rat, Alpes Maritimes, France, assignor to Aktiebolaget Kamyr, Karlstad, Sweden, a company of Sweden Filed Mar. 24, 1961, Ser. No. 98,205 Claims priority, application France Mar. 28, 1960 9 Claims. (Cl. 68-181) The present invention relates to a cylindrical upright container for washing of cellulose pulp which is supplied continuously or batchwise at the bottom of the container and is fed upwardly through the container.

The object of this invention is to provide a new and improved means for effecting an efiicient and even distributed removal of a part of the liquid content of cellulose pulp over the entire cross section of the container. This liquid may be either digesting lye or more or less pure wash water, the removal being performed by sieves not forming any appreciable obstacle to the feed of the cellulose pulp upwardly through the container towards an outlet at its top.

According to this invention, the container is diametrically divided over at least a portion of its length, and arranged closely to the partition is a sieve body. This sieve body is rotatable about an axially extending shaft within the container, and has the approximate shape of a semi-circular disc extending essentially at a right angle to the shaft. The sieve body has an apertured upper wall and an interior space in communication, via the shaft, with an outlet for the liquid sieved off thereby. By virtue of this arrangement, liquid can be screened off from the interior of the pulp column of half the container, while pulp is fed without interruption on the other side of the partition. The sieve body may be shifted in order to provide an equal treatment for the two halves.

Further objects, advantages, and novel features of the present invention will become apparent in the specification and claims, taken in connection with the accompanying drawings, wherein FIG. 1 is a elevational crosssectional view of the container taken along the broken line II in FIG. 2, FIG. 2 is a horizontal cross-sectional view taken along the line IIII in FIG. 1, FIG. 3 is an elevational cross-sectional view along the line III-III in FIG. 2, and FIG. 4 shows a modified design of a detail.

In the drawings, the numeral 11 designates an upright container having a cylindrical shell which is connected to and closed by upper and lower, domed ends forming a cover 13 and a bottom 15, respectively. The container is meant to be passed in the upward direction by cellulose pulp supplied continuously or in small batches through a supply tube 17 which may for instance be connected to the outlet end of a continuous cellulose digester or a cellulose bleach tower. The container is divided in its longitudinal direction by a flat partition 19 attached to the shell of the container and being located in an axial plane, said partition extending almost up to the cover 13. Inserted in the lower end part of the container are four hoppers 21, 23, 25 and 27, which with their lower necks 29, 31, 33 and 35, respectively, extend through the bottom of the container and which widen in the upward direction. Each one of the hoppers ends with an upper orifice having the shape of a quadrant of a circle area. The arcuate edges of said orifices bear against and are preferably connected to the shell of the container, whereas their radial straight edges join each other and preferably are connected together along horizontal lines 36, 37, 39 and 41 (FIG. 2) forming a cross.

The edges 37, 41 are located approximately opposite the horizontal lower edge 42 of the wall 19 but is separated therefrom by a small interspace. The hoppers may 3,@88,3-0fi Fatented May 7, 1963 be made of thin sheet metal and in order not to be subjected to excessively heavy stresses the dead space 43 between them and the bottom of the container, to which space the pulp should not have access, may be connected to the rest of the container in order to balance the pressure, or this space may be filled with liquid in order not to allow any greater voltune variations. The necks of the hoppers are all connected to the pulp supply pipe 17. Thus, the necks 29 and 31 are directly connected to a common pipe 45, and the necks 33 and 35 are directly connected to another common pipe 47. The pipes 45 and 47 in their turn are connected to the pipe 17. Preferably, but not necessarily, a three-way valve 49 is inserted in the connection and by means of said valve, either the hoppers 23, 21 or the hoppers 25, 27 may be connected to the pipe 17, and a shift in their connection may be made periodically. Therefore, during a certain time interval the pulp is supplied to one half of the crosssection of the container and after shifting the valve 49 said half can be shut oif and the pulp can instead be supplied to the other half of the container.

Extending between the hoppers and coaxially of the container is a hollow rotary shaft 51, the upper end of which is journalled in a bearing 53 held by the hoppers or by a spider strengthening the radial connection edges between them. The shaft 51 extends through the bottom 15 of the container and is sealed thereto by means of a sealing box 55. The shaft is driven by an electric motor 57 by means of a gear 59. By means of a sealing box 63 surrounding the shaft and radial bores the central bore 61 of the shaft is in communication with a stationary drain pipe 65 in which a controllable valve 67 is inserted.

Inserted immediately above the hopper orifices and below the diametrical wall 19 is a sieve body 69 attached to the shaft 51 and oscillatory in the horizontal plane. The sieve body has the approximate shape of a semi-circular hollow disc extending in the horizontal plane and consisting of a lower wall 71, an upper apertured wall 73, a peripheral edge lying close to the inside of the container shell, and a straight lateral edge 77 which extends diametrically of the container and with its ends joins the ends of the curved lateral edge 75. The space 79 within said sieve body is in communication with the bore of the shaft 51 and therefore also with the drain pipe 65. The apertured upper wall 73 may be flat but is preferably, as the drawings show, formed with ridges 81, 83 projecting upwardly from its fiat face and extending concentrically to the shaft 51. Said ridges may either be of a triangular cross-section, such as the ridge S1, and composed of two in opposite directions tapering truncated conical faces joining each other along an upper half-circular edge, or may be of a rectangular crosssection, such as the ridge 83, being bordered by two opposite cylindrical faces having different diameters and a connecting flat face located at a higher level than the parts of the upper wall of the sieve body lying between the ridges. Also other shapes of the ridges are possible. The faces of the ridges are perforated and by making the ridges high and close together, the sieve surface of the sieve body is increased many times as compared to a flat upper wall of the sieve body. The edge 77 and the ends of the ridges are preferably pointed in order to facilitate the turning of the sieve body.

In the position shown in the figures, the sieve body is located straight above the hoppers 21 and 23 so that the same are covered and the pulp is prevented from flowing out therefrom even if there were no valve 49. Simultaneously the space above the hoppers 25, 27 is completely left free so that the pulp flowing through the pipe 17 can be led upwardly and be evenly distributed by the hoppers over the half of the container located to the right in FIGS. 1 and 2. After oscillating the sieve body through an angle of 180 by turning the shaft 51, instead the hoppers 25, 27 are covered, whereas the pulp is let forth through the hoppers 23, 21. As indicated by the line 85, the movement of the valve 49 is coordinated with the connection of the motor 57 so that the valve is shifted simultaneously with the shifting of the sieve body be tween its two positions. The line 87 indicates a coordination also of the movement of the valve 67, the objtlalcit thereof being to close the outlet pipe 65 during the s 'fts.

In the lower edge of the vertical and diametrically extending partition 19 there are recesses 89, 91 having a shape corresponding to the shape of radial sections through, the ridges 81 and 83, respectively. The borders of said recesses lie very close to the ridges and therefore when the sieve body is oscillated, serve as scrapers for removing fibre bundles which may have stuck in the sieve holes.

Provided at the upper end of the container are means, preferably in the shape of spray tubes 93, 95, for the supply of washing liquid, such as pure water or filtrate emanating from a following wash filter and which is supplied through a pipe 97 in a quantity that may be controlled. Inserted in said pipe is a three-way valve 99, by means of which the wash liquid may be supplied either to the spray tube 93 or to the spray tube 95. The line 101 indicates a coordination of the adjustment of the valve 99 to the swinging motion of the sieve body and to other adjustments, whereby it is attained that wash liquid is supplied to that half of the container where the sieve body is temporarily located and where the pulp is at rest, whereas the other spray tube which is located above the'half whereto pulp is fed, is shut off. 103 designates a timing relay which gives the impulse to all above-mentioned adjustments and times them at suitable intervals, such as a few minutes.

A suitable overpressure may be maintained in the container by means of pressure air supplied through the pipe 105. For the discharge of pulp out of the container at its upper end there are two horizontal feed screws 107 and 109 arranged parallel-1y to each other and to the wall 19and having their ends extending into a discharge chamber 1 11 at the side of the container. In said chamber the pulp is diluted with dilution water supplied through the pipe 113 and the diluted pulp is discharged through a pulp outlet tube 115 connected to the hopper-shaped bottom of the chamber and in which tube a control valve 117 is inserted. Said valve which is controlled by means of a level controller 119 taking its impulse from the level 1-21 of pulp the discharge chamber 111, controls the discharge in such a manner that the overpressure of the container is maintained.

In the modified embodiment shown in FIG. 4 no dilution of the pulp in the discharge chamber 111 takes place.

Instead said chamber is connected to a screw press 123 V in -wlu'ch a plug is formed which is sufiiciently rigid to withstand the pressure difference prevailing, across the same, when atmospheric pressure is maintained in the discharge pipe 115.

As is apparent from the foregoing, during the operation of the plant, liquor is sieved off and washing is performed alternately in one half and the other of the container. In the shown position, the sieve body being located in the left .half of the container, said left half is operative. The pulp therein is at rest and its surface lies below the range of operation of the feed screw 107, which may be turned off. Wash water is supplied through the spray tube 93 and for-ms a layer upon the pulp, and it is spread out evenly over the pulp column and penetrates the same downwardly, displacing a corresponding volume of liquid containing a high percentage of digesting lye. The liquid located close above the sieve body 69 and having full lye strength is forced through the sieve holes into the interior of the sieve body and departs through the space 79 therein 4 and through the bore 61 and the pipe 65. The latter may lead to a plant for recovery of the heat and chemical contents of the used lye.

Simultaneously the right half of the container is inoperative in respect of washing, the spray tube being shut off and no outlet for displaced lye being provided. The pulp is fed into said half, the pulp continuously fiowing in the pipe 17 being able unobstructedly to pass from the hoppers 25, 27' further up through the container. At the upper end .of said movable pulp column which rises to a higher level than the column of the other half, the feed screw 109 is operative and discharges into the chamber 11 1 a quantity of washed pulp corresponding to the uantity of lye-containing pulp simultaneously supplied to the bottom of the container.

After the lapse of the time interval set by the timing relay 103 a shift takes place automatically, in order now to perform a washing operation in the right half of the container and to feed pulp a further step in the left half. In addition to the readjustment of the valves 49 and 99 a turning motion of the sieve body through an angle of about its axis is performed by means of the motor 57 which is automatically stopped when said motion is finished. Then the pointed straight edge 77 of the sieve body cuts itself in through the right pulp column and covers the hoppers 25, 27 with its plain lower wall 71, while the sieve body is simultaneously drawn out of the left pulpcolumn and allows the pulp to be fed out of the hoppers 2'3, 21. Now washing may take place in the right half in the same manner as earlier in the left half, and the pulp may be fed in the left half. This course is repeated periodically with regular shifts between washing of stationary pulp and feeding of the pulp without washing, and said shifts may take place with suitable intervals and with not too great steps of pulp feed between the successive washing periods. In the supply and discharge conduits common to the two container halves, the supply and the discharge :of pulp as well as of washing liquid and spent lye is essentially continuous.

Within the scope of the following claims the above described embodiment may be modified as to its details.

What is claimed is:

1. Pulp treating apparatus comprising: an upright cylindrical container having a longitudinal axis; means for supplying pulp to the lower end of said container; a partition wall extending longitudinally within said con.- tainer along at least a portion of the length thereof, and positioned to divide the interior of said container substantially two semi-circular cross-sectional portions; a shaft coaxially mounted for rotary movement within said container; a sieve body of substantially semi-circular transverse configuration cooperatively joined to said shaft in generally perpendicular relationship thereto to selectively abridge said container portions upon rotation of said shaft, said sieve body having an apertured upper wall leading to an interior chamber; and passage means in said shaft communicating with said sieve body chamber to provide an outlet for liquid drawn ofl via said apertured upper wall.

2. Apparatus defined in claim 1 further including at least two hoppers at the lower end of said container, a pulpinlet at the lower ends of each hopper, the upper end of each hopper communicating with each of said semicircular container portions.

3. Apparatus defined in claim 1 wherein said sieve body is located in a plane immediately above the upper ends of said hoppers.

4. Apparatus defined in claim 1 wherein said sieve body is located closely adjacent the bottom edge of said partition Wall and is rotatable from a position at one side of said partition wall to a position at the opposite side thereof.

5. Apparatus defined in claim 1 wherein the apertured upper wall of said sieve body includes a plurality of up- Wardly projecting ridges concentric with said shaft, whereby the surface area of said upper wall is increased. 6. Apparatus defined in claim 5 wherein the bottom edge of said partition Wall includes recesses corresponding substantially to the profile of said ridges, said ridges being operative for movement through said partition wall recesses upon rotation of said sieve body therepast.

7. Apparatus for washing of cellulose pulp comprising an upright cylindrical container, means for feeding pulp to the bottom of said container, means for supplying washing liquid to the upper part of said container, means for discharging washed pulp from the top of the container, a hollow sieve body adapted for sieving-01f part of the liquid contents of the pulp, said sieve body being located in the lower part of the container coaxially thereto, a rotary shaft coaxial to the container and extending through its bottom, said shaft supporting said sieve body and having a central bore in communication with the interior of the sieve body for letting sieved-0E liquid out of container, a vertical partition wall located above said sieve body and dividing a substantial part of the height of the container into separate compartments, and means for shifting said sieve body from a position in one compartment to a position in another compartment in order to sieve 01f liquid successively from pulp columns held by the compartments.

8. Apparatus as claimed in claim 7, in which the partition wall is situated in an axial plane of the container and the sieve body has a semicircular configuration essentially coextensive with the cross section of the compare ments on either side of the partition, whereby one compartment at a time is shut oflf from the pulp feeding means and liquid is sieved ofi the pulp therein while at rest, and simultaneously the other compartment is in open communication with the pulp feeding means.

9. Apparatus for washing of cellulose pulp, comprising an upright cylindrical container, a vertically and diametrically extending partition wall dividing said container along the greater part of its height into two compartments, means for feeding pulp in the upward direction through said container, a hollow sieve body positioned within said container, said sieve body having an upper apertured wall communicating with the hollow interior thereof and having a shape essentially corresponding to and filling out the cross-section of either one of the comparts, thereby preventing flow of pulp through one compartment while allowing flow of pulp through the other compartment, means for shifting the sieve body from one compartment to the other, means for supplying wash water to the top of the container, and means for carrying off liquid entering into the interior of the sieve body.

References Cited in the file of this patent UNITED STATES PATENTS 1,139,776 Kraus May 18, 1915 1,530,494 Heiskanen Mar. 24, 1925 FOREIGN PATENTS 60,797 Sweden May 18, 1926 

1. PULP TREATING APPARATUS COMPRISING: AN UPRIGHT CYLINDRICAL CONTAINER HAVING A LONGITUDINAL AXIS; MEANS FOR SUPPLYING PULP TO THE LOWER END OF SAID CONTAINER; A PARTITION WALL EXTENDING LONGITUDINALLY WITHIN SAID CONTAINER ALONG AT LEAST A PORTION OF THE LENGTH THEREOF, AND POSITIONED TO DIVIDE THE INTERIOR OF SAID CONTAINER SUBSTANTIALLY TWO SEMI-CIRCULAR CROSS-SECTIONAL PORTIONS; A SHAFT COAXIALLY MOUNTED FOR ROTARY MOVEMENT WITHIN SAID CONTAINER; A SIEVE BODY OF SUBSTANTIALLY SEMI-CIRCULAR TRANSVERSE CONFIGURATION COOPERATIVELY JOINED TO SAID SHAFT IN GENERALLY PERPENDICULAR RELATIONSHIP THERETO TO SELECTIVELY ABRIDGE SAID CONTAINER PORTIONS UPON ROTATION OF SAID SHAFT, SAID SIEVE BODY HAVING AN APERTURED UPPER WALL LEADING TO AN INTERIOR CHAMBER; AND PASSAGE MEANS IN SAID SHAFT COMMUNICATING WITH SAID SIEVE BODY CHAM- 